A gas separator for a submersible centrifugal pump for a well separates gas from liquid components of the well fluid. The gas separator has a rotatably driven rotor. The rotor has an outer cylinder, an inner hub and a longitudinal vane that extends between the inner hub and outer cylinder. Notches are formed in the upper edge of the vanes. A discharge member, mounted above the rotor, has a depending skirt that extends into the notches. This defines a separate inner flow path for gas to flow out of the separator into the well. The unseparated portions of the well fluid flow in a clearance between the skirt and the housing into a pump intake. Supports extend out from the discharge member for securing the discharge member in the housing.